This invention relates to projectile fuses and more particularly to fuses having an air driven generator as the electrical power source.
Various types of ordnance missiles are provided with electrical and/or electronic fuses that are target seeking. Such fuses require that a constant electrical current be supplied to fuse elements when the fuse is required to be maintained in the target seeking condition. Common types of batteries have been found to be unsuitable for this purpose. These batteries cannot be fully tested prior to their use, and become relatively inactive at low temperatures. Reserve type batteries designed for low temperature operation are not completely satisfactory due to their requirements for and sensitivity to the spin of the projectile fuse.
Generators provided with wind vances or air driven turbines have ben used and have given satisfactory performance. A common approach has been to ram air into and through a central axial bore located in the nose of the fuse. The rotating turbine includes a generator rotor, a central axial shaft therefor, and bearing means rotatably suppporting the shaft. The turbine is rotated by the axial flow of ram air to drive a generator that supplies the fuse with electrical power. This approach is not satisfactory for use with fuses that utilize radio frequency or optical firing systems. Such systems require that the projectile nose be devoted to target seeking or detection means, such as an antenna, lens, or optical path responsive devices. Furthermore, since the electrical signals from these devices are typically very weak, part of the target signal detection processor should be located as close to the antenna or optical system as possible, preferably back to back. These two requirements preclude the use of a power generator that must either draw air in from a central bore or have a turbine rotating about a central axial shaft, since both must occupy critical interal volume along the longitudinal axis of the projectile.
A more ideal fuse would be one that permits the target seeking and processing apparatus to be housed in the forwardmost section of the fuse in such a manner that the seeking means have an unobstructed view and be adjacent the processing means, and one which provides an electrical power generating source that does not alter the projectile's exterior geometry or consume excessive fuse internal volume.